/**
 * 
 */
package com.work.cos.util.thirdpay.alipay.sign;

import java.io.UnsupportedEncodingException;

/**
 * A very common task when working with Webservices, is to encode/decode specific URI components
 * 
 * @author sam
 *
 */
public class URIComponent
{
    public static final String ALLOWED_CHARS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.!~*'()";

    public static String encodeURIComponent(String input)
    {
        if (null == input || "".equals(input))
        {
            return input;
        }

        int l = input.length();
        StringBuilder o = new StringBuilder(l * 3);
        try
        {
            for (int i = 0; i < l; i++)
            {
                String e = input.substring(i, i + 1);
                if (ALLOWED_CHARS.indexOf(e) == -1)
                {
                    byte[] b = e.getBytes("utf-8");
                    o.append(getHex(b));
                    continue;
                }
                o.append(e);
            }
            return o.toString();
        }
        catch (UnsupportedEncodingException e)
        {
            e.printStackTrace();
        }
        return input;
    }

    private static String getHex(byte buf[])
    {
        StringBuilder o = new StringBuilder(buf.length * 3);
        for (int i = 0; i < buf.length; i++)
        {
            int n = (int) buf[i] & 0xff;
            o.append("%");
            if (n < 0x10)
            {
                o.append("0");
            }
            o.append(Long.toString(n, 16).toUpperCase());
        }
        return o.toString();
    }

    public static String decodeURIComponent(String encodedURI)
    {
        char actualChar;

        StringBuffer buffer = new StringBuffer();

        int bytePattern, sumb = 0;

        for (int i = 0, more = -1; i < encodedURI.length(); i++)
        {
            actualChar = encodedURI.charAt(i);

            switch (actualChar)
            {
            case '%':
            {
                actualChar = encodedURI.charAt(++i);
                int hb = (Character.isDigit(actualChar) ? actualChar - '0' : 10 + Character.toLowerCase(actualChar) - 'a') & 0xF;
                actualChar = encodedURI.charAt(++i);
                int lb = (Character.isDigit(actualChar) ? actualChar - '0' : 10 + Character.toLowerCase(actualChar) - 'a') & 0xF;
                bytePattern = (hb << 4) | lb;
                break;
            }
            case '+':
            {
                bytePattern = ' ';
                break;
            }
            default:
            {
                bytePattern = actualChar;
            }
            }

            if ((bytePattern & 0xc0) == 0x80)
            { // 10xxxxxx
                sumb = (sumb << 6) | (bytePattern & 0x3f);
                if (--more == 0)
                    buffer.append((char) sumb);
            }
            else if ((bytePattern & 0x80) == 0x00)
            { // 0xxxxxxx
                buffer.append((char) bytePattern);
            }
            else if ((bytePattern & 0xe0) == 0xc0)
            { // 110xxxxx
                sumb = bytePattern & 0x1f;
                more = 1;
            }
            else if ((bytePattern & 0xf0) == 0xe0)
            { // 1110xxxx
                sumb = bytePattern & 0x0f;
                more = 2;
            }
            else if ((bytePattern & 0xf8) == 0xf0)
            { // 11110xxx
                sumb = bytePattern & 0x07;
                more = 3;
            }
            else if ((bytePattern & 0xfc) == 0xf8)
            { // 111110xx
                sumb = bytePattern & 0x03;
                more = 4;
            }
            else
            { // 1111110x
                sumb = bytePattern & 0x01;
                more = 5;
            }
        }
        return buffer.toString();
    }

    public static void main(String args[])
    {
        String s = "Fgah7PL9053jBMPU0CIgq5Vui2zFsvF+7M1Aw1PH+qSHSw4nNLuZcdNANnOJFSvdL7zDQbE0R50otXWWy9XjyA2gfzhr0heLbz0+JiDsspFmG+ARH5L+WOFLqxTAIIAvKW8SU7aQ/q1rpW9vSH137K//FO2TnNI5raU/mEn9jb4=";
        // Fgah7PL9053jBMPU0CIgq5Vui2zFsvF%2B7M1Aw1PH%2BqSHSw4nNLuZcdNANnOJFSvdL7zDQbE0R50otXWWy9XjyA2gfzhr0heLbz0%2BJiDsspFmG%2BARH5L%2BWOFLqxTAIIAvKW8SU7aQ%2Fq1rpW9vSH137K%2F%2FFO2TnNI5raU%2FmEn9jb4%3D
        System.out.println(encodeURIComponent(s));
    }
}
